Conventionally, in order to improve working efficiency in work machines, such as construction machines, and the like, machines equipped with a plurality of different operating units have been proposed.
For example, in a work machine equipped with a loading operating unit for performing loading operations by means of a loading bucket and an excavating operating unit for performing excavating operations by means of a digging bucket, the aforementioned loading operating unit and excavating operating unit can be operated in coordination with each other, in such a manner that soil generated by the excavating operation can be loaded and removed directly, thereby improving the working efficiency.
A work machine such as that as described above generally comprises a traveling base which travels by means of crawler treads or wheels, and a swiveling base provided rotatably on the upper portion of the traveling base, in such a manner that one operating unit can be supported on the swiveling base to form an upper operating unit, whilst another operating unit is supported on the traveling base to form a lower operating unit.
In a work machine having this composition, the orientation of the upper operating unit can be changed as desired, by causing the swiveling base to swivel in an appropriate direction with respect to the traveling base, and hence work can be carried out by the upper operating unit throughout a range of 360.degree., regardless of the orientation of the traveling base.
However, the operational range of the lower operating unit is restricted by the orientation of the traveling base, and therefore the range in which coordinated operation of the upper operating unit and the lower operating unit can be performed is limited to the operational range of the lower operating unit, unless the orientation of the traveling base is changed.
In other words, with a conventional work machine as described above, in cases where coordinated operation of the upper operating unit and lower operating unit is to be performed over a wide range, the orientation of the traveling base must be changed, each time the range of coordinated operation exceeds the operational range of the lower operating unit, thereby leading to a decline in working efficiency corresponding to the amount of work involved in changing the orientation of the traveling base.
In view of these circumstances, Japanese Utility Model Application Laid-open No. 37877/1993, for example, describes a crane, wherein a swiveling unit is attached rotatably to the upper portion of a frame equipped with an outrigger, and furthermore, a traveling base is attached rotatably to the lower portion of the frame. Moreover, Japanese Patent Application Laid-open No. 173295/1994 discloses an excavating device with conveyor, wherein a first swiveling unit is installed on a lower traveling unit via a first swiveling device, a second swiveling unit is installed on top of the first swiveling unit via a second swiveling device, and a conveyor is attached to the side portion of the first swiveling unit, whilst an excavating front unit is attached to the second swiveling unit.
According to the crane disclosed in Japanese Utility Model Application Laid-open No. 37877/1993, the outrigger can be orientated in any direction by swiveling the frame, and moreover, the crane can be orientated in any direction with respect to the traveling unit and the outrigger by causing the swiveling unit to swivel. Furthermore, in the excavating device with conveyor disclosed in Japanese Patent Application Laid-open No. 173295/1994, the conveyor can be orientated in any direction with respect to the power traveling unit by causing the first swiveling unit to swivel, and the excavating front unit can be orientated in any direction with respect to the lower traveling unit and the conveyor by causing the second swiveling unit to swivel.
However, in the work machines disclosed in the aforementioned patent specifications, neither the detailed composition of the swiveling mechanism nor the detailed composition of the mode for connecting hydraulic circuits is described in either case, and hence there is the risk that various problems will arise at the stage of practical implementation.
Moreover, a work machine provided with two swiveling mechanisms has also been proposed, for instance, in Japanese Patent Application Laid-open No. 165392/1995, wherein a swiveling unit is installed on a traveling unit by means of a first swiveling mechanism, and a crane is provided on this swiveling unit in an eccentric position with respect to the first swiveling mechanism, by means of a second swiveling mechanism.
However, the device disclosed in Japanese Patent Application Laid-Open No. 165392/1995 is equipped only with a crane as an operating unit, and hence it, is not capable of performing coordinated operations involving operating units of a plurality of different types.
With the foregoing in view, it is an object of the present invention to achieve a work machine whereby coordinated operations involving operating units of a plurality of different types can be performed in an efficient manner.
Moreover, it is a further object of the present invention to provide a novel work machine whereby coordinated operations involving operating units of a plurality of different types can be performed in an efficient manner.